n8n-expression-syntax

Access webhook data in n8n expressions by referencing the nested payload structure using `{{$json.body.field_name}}`. Directly calling `{{$json.field_name}}` fails because webhook payloads are wrapped inside the `body` object, so you must explicitly traverse `body` to retrieve values correctly.

The correct syntax for n8n expressions requires wrapping variables in double curly braces `{{ }}`. You can reference workflow data using variables like `$json`, `$node`, `$now` for timestamps, and `$env` for environment variables to dynamically inject values into node parameters.

Your n8n expression returns undefined when the data structure does not match your reference path. If you are working with webhook data, you must access fields via `$json.body` instead of `$json` directly, ensuring the expression path matches the incoming JSON payload structure.

Yes, you can use environment variables inside n8n expression syntax by wrapping them in `{{$env.VARIABLE_NAME}}`. This allows you to securely inject credentials and configuration values into your workflow without hardcoding sensitive data directly into the node parameters.

Common limitations of n8n expressions include failing to use `{{ }}` braces, incorrectly accessing webhook payloads via `$json` instead of `$json.body`, and referencing undefined `$node` names. Understanding these structural constraints is essential to avoid workflow execution errors.